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/* guestfish - the filesystem interactive shell
* Copyright (C) 2010 Red Hat Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <inttypes.h>
#include <sys/types.h>
#include <sys/stat.h>
#include "fish.h"
#define MAX_DOWNLOAD_SIZE (16 * 1024 * 1024)
#define MAX_DOWNLOAD_SIZE_TEXT "16MB"
static off_t get_size (const char *filename);
int
run_hexedit (const char *cmd, int argc, char *argv[])
{
if (argc < 1 || argc > 3) {
fprintf (stderr, _("hexedit (device|filename) [max | start max]\n"));
return -1;
}
const char *filename = argv[0];
off_t size = get_size (filename);
if (size == -1)
return -1;
if (size == 0) {
fprintf (stderr,
_("hexedit: %s is a zero length file or device\n"), filename);
return -1;
}
off_t start;
off_t max;
if (argc == 1) { /* hexedit device */
/* Check we're not going to download a huge file. */
if (size > MAX_DOWNLOAD_SIZE) {
fprintf (stderr,
_("hexedit: %s is larger than %s. You must supply a limit using\n"
" 'hexedit %s <max>' (eg. 'hexedit %s 1M') or a range using\n"
" 'hexedit %s <start> <max>'.\n"),
filename, MAX_DOWNLOAD_SIZE_TEXT,
filename, filename,
filename);
return -1;
}
start = 0;
max = size;
}
else {
if (argc == 3) { /* hexedit device start max */
if (parse_size (argv[1], &start) == -1)
return -1;
if (parse_size (argv[2], &max) == -1)
return -1;
} else { /* hexedit device max */
start = 0;
if (parse_size (argv[1], &max) == -1)
return -1;
}
if (start + max > size)
max = size - start;
}
if (max <= 0) {
fprintf (stderr, _("hexedit: invalid range\n"));
return -1;
}
/* Download the requested range from the remote file|device into a
* local temporary file.
*/
const char *editor;
int r;
struct stat oldstat, newstat;
char buf[BUFSIZ];
char tmp[] = "/tmp/guestfishXXXXXX";
int fd = mkstemp (tmp);
if (fd == -1) {
perror ("mkstemp");
return -1;
}
/* Choose an editor. */
editor = getenv ("HEXEDITOR");
if (editor == NULL)
editor = "hexedit";
snprintf (buf, sizeof buf, "/dev/fd/%d", fd);
if (guestfs_download_offset (g, filename, buf, start, max) == -1) {
unlink (tmp);
close (fd);
return -1;
}
if (close (fd) == -1) {
unlink (tmp);
return -1;
}
/* Get the old stat. */
if (stat (tmp, &oldstat) == -1) {
perror (tmp);
unlink (tmp);
return -1;
}
/* Edit it. */
snprintf (buf, sizeof buf, "%s %s", editor, tmp);
r = system (buf);
if (r != 0) {
perror (buf);
unlink (tmp);
return -1;
}
/* Get the new stat. */
if (stat (tmp, &newstat) == -1) {
perror (tmp);
unlink (tmp);
return -1;
}
/* Changed? */
if (oldstat.st_ctime == newstat.st_ctime &&
oldstat.st_size == newstat.st_size) {
unlink (tmp);
return 0;
}
/* Write new content. */
if (guestfs_upload_offset (g, tmp, filename, start) == -1) {
unlink (tmp);
return -1;
}
unlink (tmp);
return 0;
}
/* Get the size of the file or block device. */
static off_t
get_size (const char *filename)
{
int64_t size;
if (STRPREFIX (filename, "/dev/")) {
size = guestfs_blockdev_getsize64 (g, filename);
if (size == -1)
return -1;
}
else {
size = guestfs_filesize (g, filename);
if (size == -1)
return -1;
}
/* This case should be safe because we always compile with
* 64 bit file offsets.
*/
return (off_t) size;
}
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